Sand, Ruku Pichincha, Quito, Ecuador
                These are the minerals with a density greater than 2.8
                  grams per cubic centimeter. Hornblendes are one of the major groups
                  of minerals in this collection. With reflected darkfield illumination the glassy
                  coating becomes visible on many of the particles.
              
              
                Reflected Darkfield Illumination
                
Definition/Function:
                Significance in the Environment:
                Characteristic Features:
                Associated Particles:
                References:
                Greenberg, Gary, A GRAIN OF SAND: NATURE'S SECRET WONDER, Voyageur Press, 2008.
                
                Welland, Michael, SAND: THE NEVER ENDING STORY, University of California Press, 2009.
                
                http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artjun01/clsand.html
                
(Good Information on the microscopy of sand, Great site for more information on
                microscopy in general)
                
                http://www.scientificamerican.com/article.cfm?id=a-grain-of-sand-natures-secret-wonder
                
(Good Information on Sand with links to more information on sand)
                
                http://www.sciencelive.org/component/option,com_mediadb/task,play/idstr,Open-feeds_fsc_exploring_sedimentary_processes_fsc02_02_m4v/vv,-2/Itemid,97
                
(Brief, very informative video on what can be learned from the shape of a sand
                grain.)